Python asyncio loops and fan-out. TRIGGER when: an `async def` loops or has `await` inside a `for`/`while`; the same coroutine runs once per item; adding or reviewing `asyncio.gather`, `TaskGroup`, `as_completed`, `create_task` or a `Semaphore`; async code is slow, hangs, over-requests, or logs "Task exception was never retrieved". SKIP when: synchronous code, or async with no loop and no concurrency.
